GDALWarpResolveWorkingDataType(): ignore srcNoDataValue if it doesn't…

… fit into the data type of the source band
OSGeo · Sep 1, 2024 · 45a5f0a · 45a5f0a
1 parent f5c3e40
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diff --git a/alg/gdalwarper.cpp b/alg/gdalwarper.cpp
@@ -1533,6 +1533,32 @@ void CPL_STDCALL GDALWarpResolveWorkingDataType(GDALWarpOptions *psOptions)
 
     psOptions->eWorkingDataType = GDT_Byte;
 
+    // If none of the provided input nodata values can be represented in the
+    // data type of the corresponding source band, ignore them.
+    if (psOptions->hSrcDS && psOptions->padfSrcNoDataReal)
+    {
+        int nCountInvalidSrcNoDataReal = 0;
+        for (int iBand = 0; iBand < psOptions->nBandCount; iBand++)
+        {
+            GDALRasterBandH hSrcBand = GDALGetRasterBand(
+                psOptions->hSrcDS, psOptions->panSrcBands[iBand]);
+
+            if (hSrcBand &&
+                !GDALIsValueExactAs(psOptions->padfSrcNoDataReal[iBand],
+                                    GDALGetRasterDataType(hSrcBand)))
+            {
+                nCountInvalidSrcNoDataReal++;
+            }
+        }
+        if (nCountInvalidSrcNoDataReal == psOptions->nBandCount)
+        {
+            CPLFree(psOptions->padfSrcNoDataReal);
+            psOptions->padfSrcNoDataReal = nullptr;
+            CPLFree(psOptions->padfSrcNoDataImag);
+            psOptions->padfSrcNoDataImag = nullptr;
+        }
+    }
+
     for (int iBand = 0; iBand < psOptions->nBandCount; iBand++)
     {
         if (psOptions->hDstDS != nullptr)

diff --git a/autotest/cpp/test_alg.cpp b/autotest/cpp/test_alg.cpp
@@ -151,6 +151,35 @@ TEST_F(test_alg, GDALWarpResolveWorkingDataType_padfSrcNoDataReal)
     GDALDestroyWarpOptions(psOptions);
 }
 
+// GDALWarpResolveWorkingDataType: effect of padfSrcNoDataReal
+TEST_F(test_alg, GDALWarpResolveWorkingDataType_padfSrcNoDataReal_with_band)
+{
+    GDALDatasetUniquePtr poDS(GDALDriver::FromHandle(GDALGetDriverByName("MEM"))
+                                  ->Create("", 1, 1, 1, GDT_Byte, nullptr));
+    GDALWarpOptions *psOptions = GDALCreateWarpOptions();
+    psOptions->hSrcDS = GDALDataset::ToHandle(poDS.get());
+    psOptions->nBandCount = 1;
+    psOptions->panSrcBands =
+        static_cast<int *>(CPLMalloc(psOptions->nBandCount * sizeof(int)));
+    psOptions->panSrcBands[0] = 1;
+    psOptions->padfSrcNoDataReal =
+        static_cast<double *>(CPLMalloc(sizeof(double)));
+    psOptions->padfSrcNoDataReal[0] = 0.0;
+    GDALWarpResolveWorkingDataType(psOptions);
+    EXPECT_EQ(psOptions->eWorkingDataType, GDT_Byte);
+
+    psOptions->padfSrcNoDataReal[0] = -1.0;
+    GDALWarpResolveWorkingDataType(psOptions);
+    EXPECT_EQ(psOptions->eWorkingDataType, GDT_Byte);
+
+    psOptions->eWorkingDataType = GDT_Unknown;
+    psOptions->padfSrcNoDataReal[0] = 2.0;
+    GDALWarpResolveWorkingDataType(psOptions);
+    EXPECT_EQ(psOptions->eWorkingDataType, GDT_Byte);
+
+    GDALDestroyWarpOptions(psOptions);
+}
+
 // GDALWarpResolveWorkingDataType: effect of padfSrcNoDataImag
 TEST_F(test_alg, GDALWarpResolveWorkingDataType_padfSrcNoDataImag)
 {